Sedimentary Rock (Metamorphosed)

Rounded quartz-rich sandstone or quartzite cobble

Quartz-dominated siliciclastic rock; likely sandstone, possibly weakly metamorphosed quartzite

Quartzite River Pebble

Metamorphosed Quartz Sandstone (SiO2)

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Dark gray slate (possibly argillite or shale)

Slate, a low-grade metamorphic rock derived mainly from shale; composition commonly quartz, illite/muscovite, chlorite, and clay minerals

Greenstone / Greenschist

Metamorphosed mafic igneous rock (Greenschist facies)

Greenstone Celt (Polished Stone Axe)

Metamorphosed mafic rock (often Basalt or Diabase)

Quartzite with Epidote Vein

Metamorphosed Quartz Sandstone with Hydrothermal Vein

Banded iron formation (iron-rich metamorphic rock)

Banded iron formation (BIF), chiefly hematite/magnetite with chert or quartz (Fe₂O₃/Fe₃O₄ and SiO₂)

Red Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Quartzite (Tumbled Pebble)

Metamorphosed Quartz Sandstone (SiO2)

Slate

Slate (Metamorphosed Mudstone/Shale)

Argillite (with Barnacles)

Argillite (metamorphosed mudstone/shale)

Rounded light-colored pebble, likely quartz-rich sandstone or quartzite

Unidentified quartz-rich rock; exact identification requires close examination or testing

Weathered quartz-rich pebble

Likely quartzite or milky vein quartz; exact identification is uncertain from the image

Rounded brown pebble, likely quartzite

Quartzite (predominantly interlocking quartz, SiO₂); identification is tentative from the photo

Weathered quartz-rich rock, possibly quartzite or granitic fragment

Indeterminate; likely quartzite (mostly SiO₂) or quartz-bearing granitoid

Tumbled quartzite or quartz-rich beach stone

Quartzite; predominantly microcrystalline quartz (SiO₂)

Greenstone (likely serpentinite or chlorite-rich schist)

Serpentinite: Mg-rich phyllosilicates, chiefly antigorite/lizardite; possible chlorite-actinolite schist

Tumbled green aventurine (probable)

Quartzite dominated by quartz (SiO₂), with green mica/fuchsite or chlorite inclusions

Likely weathered granite or granitic gneiss

Granite: quartz + feldspar + mica; possibly gneiss if the faint texture reflects foliation

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

White Marble

Metamorphosed Limestone (principally CaCO3)

Greenstone (likely altered basalt)

Chlorite- and/or epidote-altered mafic volcanic rock; exact identification needs close examination

Tumbled green aventurine

Quartz (SiO₂) containing green fuchsite mica inclusions; a variety of quartzite

Quartzite River Stone

Quartzite (SiO2)

Quartzite with Iron Inclusions

Metamorphosed Quartz-rich Rock (SiO2 with Fe2O3)

Quartzite

Quartzite (Metamorphosed Quartz Sandstone)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Quartz-bearing mica schist

Mica schist, likely quartz–muscovite/biotite schist

Quartz-rich river pebble, possibly quartzite

Quartz (SiO₂); possibly quartzite, a rock composed predominantly of recrystallized quartz

Quartzite with Iron Inclusions

Metamorphosed Sandstone (SiO2 dominated)

Quartzite Cobble with Iron Staining

Metamorphosed Quartz Sandstone (SiO2)

Quartz-bearing rock fragment, likely quartz vein in basalt or dark host rock

Quartz (SiO₂) with probable mafic host, possibly basalt or amphibolite

Quartz-rich metamorphic rock, likely quartzite or vein quartz

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica and feldspar

Chlorite-rich metamorphic rock, likely greenschist

Greenschist; commonly composed of chlorite, actinolite, epidote, albite, and quartz

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Likely quartz-rich stone (possibly milky quartz or quartzite)

Quartz, silicon dioxide (SiO₂), or quartzite if interlocking grains are present

Quartzite

Quartzite (Metamorphosed Quartz Sandstone)

Likely epidote-bearing rock or weathered chalcopyrite specimen

Epidote-group mineral, possibly with chalcopyrite; identification uncertain from image

Polished bronzite-rich serpentinized rock

Serpentinite or serpentinized peridotite, likely containing bronzite (orthopyroxene) and magnetite

Quartzite River Rock

Metamorphosed Quartz-rich Sandstone (SiO2)